Imaging apparatus and distance measuring apparatus using the same

Abstract

An imaging apparatus in an embodiment includes lens optical systems each including a lens whose surface closest to the target object is shaped to be convex toward the target object, imaging regions which respectively face the lens optical systems and output a photoelectrically converted signal corresponding to an amount of light transmitting the lens optical systems and received by the imaging regions, and a light-transmissive cover which covers an exposed portion of the lens of each of the lens optical systems and a portion between the lens of one of the lens optical systems and the lens of another one of the lens optical systems adjacent to the one of the lens optical systems, the cover having a curved portion which is convex toward the target object. The optical axes of the lens optical systems are parallel to each other.

What is claimed is: 
     
       1. An imaging apparatus for capturing an image of a target object, comprising:
 a casing; 
 lens optical systems each including a lens whose surface closest to the target object is shaped to be convex toward the target object; 
 light detection cells which respectively face the lens optical systems and output a photoelectrically converted signal corresponding to an amount of light transmitting through the lens optical systems and received by the light detection cells; and 
 a cover which covers an exposed portion of the lens of each of the lens optical systems and a portion between the lens of one of the lens optical systems and the lens of another one of the lens optical systems adjacent to the one of the lens optical systems, the cover having a curved portion which is convex toward the target object, wherein 
 optical axes of the lens optical systems are parallel to each other, 
 wherein the cover is light-transmissive at least from said exposed portion of the lens of each of the lens optical systems to said portion between the lens of one of the lens optical systems and the lens of another one of the lens optical systems adjacent to the one of the lens optical systems, and 
 the cover is disposed on the casing such that the curved portion extends beginning from the casing at a position, the position being between a top and bottom of each of the lenses in an optical axis direction of the lens optical systems. 
 
     
     
       2. The imaging apparatus according to  claim 1 , wherein the lens of each of the lens optical systems is a concave meniscus lens. 
     
     
       3. The imaging apparatus according to  claim 1 , wherein the cover covers an entire exposed portion of the lens optical systems on a target object side. 
     
     
       4. The imaging apparatus according to  claim 1 , wherein the cover is made of glass. 
     
     
       5. The imaging apparatus according to  claim 4 , wherein the lens of each of the lens optical systems is made of resin. 
     
     
       6. The imaging apparatus according to  claim 1 , wherein each of the lens optical systems has an angle of view of 120° or more in at least one direction. 
     
     
       7. The imaging apparatus according to  claim 1 , wherein the cover is water repellent. 
     
     
       8. The imaging apparatus according to  claim 1 , wherein |f 0 |>50 fx is satisfied, where f 0  represents a focal length of the cover and fx represents the focal length of each of the lens optical systems. 
     
     
       9. The imaging apparatus according to  claim 1 , wherein
 each of the lens optical systems includes n single lenses including the lens, n being an integer greater than 0, and 
 a k-th single lens from a target-object-side end of each of the lens optical systems, k being an integer greater than 0 and equal to or less than n, is integrally formed with a k-th single lens from a target-object-side end of another lens optical system. 
 
     
     
       10. The imaging apparatus according to  claim 9 , wherein all single lenses included in each of the lens optical systems are integrally formed with the single lenses of another lens optical system that are located at corresponding positions. 
     
     
       11. The imaging apparatus according to  claim 1 , wherein the light detection cells are provided in a single image sensor. 
     
     
       12. The imaging apparatus according to  claim 1 , wherein the light detection cells are respectively provided in a plurality of image sensors. 
     
     
       13. The imaging apparatus according to  claim 1 , further comprising:
 body tubes each housing the lens of each of the lens optical systems, wherein 
 a minimum distance between adjacent body tubes is 15 mm or less. 
 
     
     
       14. The imaging apparatus according to  claim 1 , wherein an angle between the optical axis of each of the lens optical systems and a normal to a tangent line at an end of an effective diameter of the cover across which light from the target object passes through is 75 degrees or less. 
     
     
       15. The imaging apparatus according to  claim 1 , wherein
 the lens optical systems are arranged in one direction, and 
 a cross section of the cover that is perpendicular to the one direction has an arch shape. 
 
     
     
       16. The imaging apparatus according to  claim 1 , wherein
 the cover has a dome shape. 
 
     
     
       17. A distance measuring apparatus comprising:
 an imaging apparatus for capturing an image of a target object, including:
 a casing; 
 lens optical systems each including a lens whose surface closest to the target object is shaped to be convex toward the target object; 
 light detection cells which respectively face the lens optical systems and output a photoelectrically converted signal corresponding to an amount of received light; and 
 a cover which covers an exposed portion of the lens of each of the lens optical systems and a portion between the lens of one of the lens optical systems and the lens of a lens optical system adjacent to the one of the lens optical systems, the cover having a dome shape which is convex toward the target object, 
 wherein optical axes of the lens optical systems are parallel to each other, 
 wherein the cover is light-transmissive at least from said exposed portion of the lens of each of the lens optical systems to said portion between the lens of one of the lens optical systems and the lens of a lens optical system adjacent to the one of the lens optical systems, and 
 wherein the cover is disposed on the casing such that the dome shape extends beginning from the casing at a position, the position being between a top and bottom of each of the lenses in an optical axis direction of the lens optical systems; and 
 
 a computation circuit, wherein 
 in operation, the computation circuit measures a distance to a target object based on a parallax of the target object in images obtained in the light detection cells of the imaging apparatus. 
 
     
     
       18. The distance measuring apparatus according to  claim 17 , further comprising:
 an output device that outputs information corresponding to the distance measured by the computation circuit. 
 
     
     
       19. An imaging apparatus for capturing an image of a target object, comprising:
 lens optical systems each including a lens whose surface closest to the target object is shaped to be convex toward the target object; 
 light detection cells which respectively face the lens optical systems and output a photoelectrically converted signal corresponding to an amount of light transmitting through the lens optical systems and received by the light detection cells; 
 a cover which covers an exposed portion of the lens of each of the lens optical systems and a portion between the lens of one of the lens optical systems and the lens of another one of the lens optical systems adjacent to the one of the lens optical systems, the cover having a curved portion which is convex toward the target object; and 
 retainers each retaining one of the lenses having the surface closest to the target object be shaped to be convex toward the target object, wherein 
 optical axes of the lens optical systems are parallel to each other, 
 wherein the cover is light-transmissive at least from said exposed portion of the lens of each of the lens optical systems to said portion between the lens of one of the lens optical systems and the lens of another one of the lens optical systems adjacent to the one of the lens optical systems, and 
 wherein the surface of each of the lenses protrudes outwardly from the retainers, respectively. 
 
     
     
       20. The imaging apparatus according to  claim 1 , wherein each of the lenses comprises a plurality of lenses. 
     
     
       21. The distance measuring apparatus according to  claim 17 , wherein each of the lenses comprises a plurality of lenses.